mouse_send_command(0xF3); // Set sample rate mouse_send_command(200); mouse_send_command(0xF3); mouse_send_command(100); mouse_send_command(0xF3); mouse_send_command(80); mouse_send_command(0xF2); // Get device ID – should return 3
int mouse_send_command(uint8_t cmd) // Wait until input buffer is empty while (inb(0x64) & 2); outb(0x64, 0xD4); // Tell controller next byte is for mouse while (inb(0x64) & 2); outb(0x60, cmd); // Wait for ACK uint8_t ack = 0; int timeout = 100000; while (timeout-- && !(inb(0x64) & 1)); if (timeout <= 0) return -1; ack = inb(0x60); return (ack == 0xFA) ? 0 : -1; ps/2 compatible mouse driver
Developing a driver for a PS/2 mouse requires a distinct separation of concerns: the driver must first interface with the 8042 Super I/O controller (the keyboard controller) to enable the mouse channel, and subsequently interface directly with the mouse hardware to interpret movement and button state data. This paper outlines a driver model suitable for a monolithic kernel or embedded system where direct hardware access is permitted. PS/2 commands are sent via port 0x64 , then data via 0x60
PS/2 commands are sent via port 0x64 , then data via 0x60 . The mouse acknowledges each command with 0xFA . // Set sample rate mouse_send_command(200)
Reading port 0x64 returns a status byte with the following critical bits: